• Manager says team must be wary despite 3-2 lead over Schalke• Ilkay Gundogan admits he could leave City this summer

Pep Guardiola has given Manchester City a reality check by stating they are “still teenagers” in the Champions League.

City hold a 3-2 advantage over Schalke before Tuesday night’s last-16 second leg at the Etihad Stadium. While this makes them favourites to progress Guardiola pointed to City’s relative inexperience when asked what is required for the club to be considered a true continental heavyweight. This is their eighth season in the Champions League and the sixth time they have qualified for the knockout rounds. The furthest they have reached is the semi-finals, losing to Real Madrid 1-0 on aggregate in 2016.